Elaborate alarm switches have been developed over the years, but they are much too complex and are not practical for numerous situations and environments. U.S. Pat. Nos. 4,258,358 and 5,332,992 disclose and claim just two of numerous security alarm systems. Such systems are usually mounted on or within stationary doors or window frames of finished structures and require electrical leads from the switch to the alarm control box. U.S. Pat. No. 5,332,992 discloses and claims an alarm switch assembly for a door or window. Another category of alarm systems are those that detect forced entry at any section of fencing between vertical posts; see U.S. Pat. Nos. 4,005,397; 4,829,287 and 5,438,316. None of these patents address the problem of entry through a gate.
There is a need for a non-complex system for signaling the unauthorized entry through a gate or other movable barrier that does not have a latch. A few examples of numerous situations where there is a need for such a non-complex system include a gate in a farm or ranch fence, a gate in commercial and residential fencing and a gate to protect personnel from hazardous areas, e.g. construction and demolition sites, mine shafts and the like.